From 523db20c11e8a52c32d173e46950ac01f95dc96b Mon Sep 17 00:00:00 2001
From: Jin Young Park <jy2045@sogang.ac.kr>
Date: Thu, 17 Sep 2020 03:22:49 +0900
Subject: [PATCH] [Fix] `destructuring-assignment`: Handle destructuring of
 useContext in SFC

Co-authored-by: Jin Young Park <jy2045@sogang.ac.kr>
Co-authored-by: Jordan Harband <ljharb@gmail.com>
---
 lib/rules/destructuring-assignment.js       | 36 +++++++-
 tests/lib/rules/destructuring-assignment.js | 96 ++++++++++++++++++++-
 2 files changed, 128 insertions(+), 4 deletions(-)

diff --git a/lib/rules/destructuring-assignment.js b/lib/rules/destructuring-assignment.js
index 2536bd671d..9652e37fcf 100644
--- a/lib/rules/destructuring-assignment.js
+++ b/lib/rules/destructuring-assignment.js
@@ -8,6 +8,7 @@ const Components = require('../util/Components');
 const docsUrl = require('../util/docsUrl');
 const isAssignmentLHS = require('../util/ast').isAssignmentLHS;
 const report = require('../util/report');
+const testReactVersion = require('../util/version').testReactVersion;
 
 const DEFAULT_OPTION = 'always';
 
@@ -94,6 +95,8 @@ module.exports = {
     const destructureInSignature = (context.options[1] && context.options[1].destructureInSignature) || 'ignore';
     const sfcParams = createSFCParams();
 
+    // set to save renamed var of useContext
+    const contextSet = new Set();
     /**
      * @param {ASTNode} node We expect either an ArrowFunctionExpression,
      *   FunctionDeclaration, or FunctionExpression
@@ -128,7 +131,7 @@ module.exports = {
     function handleSFCUsage(node) {
       const propsName = sfcParams.propsName();
       const contextName = sfcParams.contextName();
-      // props.aProp || context.aProp
+      // props.aProp
       const isPropUsed = (
         (propsName && node.object.name === propsName)
           || (contextName && node.object.name === contextName)
@@ -142,6 +145,16 @@ module.exports = {
           },
         });
       }
+
+      // const foo = useContext(aContext);
+      // foo.aProp
+      const isContextUsed = contextSet.has(node.object.name) && !isAssignmentLHS(node);
+      if (isContextUsed && configuration === 'always') {
+        context.report({
+          node,
+          message: `Must use destructuring ${node.object.name} assignment`,
+        });
+      }
     }
 
     function isInClassProperty(node) {
@@ -176,8 +189,9 @@ module.exports = {
       }
     }
 
-    return {
+    const hasHooks = testReactVersion(context, '>= 16.9');
 
+    return {
       FunctionDeclaration: handleStatelessComponent,
 
       ArrowFunctionExpression: handleStatelessComponent,
@@ -212,13 +226,29 @@ module.exports = {
         const SFCComponent = components.get(context.getScope(node).block);
 
         const destructuring = (node.init && node.id && node.id.type === 'ObjectPattern');
+        const identifier = (node.init && node.id && node.id.type === 'Identifier');
         // let {foo} = props;
-        const destructuringSFC = destructuring && (node.init.name === 'props' || node.init.name === 'context');
+        const destructuringSFC = destructuring && node.init.name === 'props';
+        // let {foo} = useContext(aContext);
+        const destructuringUseContext = hasHooks && destructuring && node.init.callee && node.init.callee.name === 'useContext';
+        // let foo = useContext(aContext);
+        const assignUseContext = hasHooks && identifier && node.init.callee && node.init.callee.name === 'useContext';
         // let {foo} = this.props;
         const destructuringClass = destructuring && node.init.object && node.init.object.type === 'ThisExpression' && (
           node.init.property.name === 'props' || node.init.property.name === 'context' || node.init.property.name === 'state'
         );
 
+        if (SFCComponent && assignUseContext) {
+          contextSet.add(node.id.name);
+        }
+
+        if (SFCComponent && destructuringUseContext && configuration === 'never') {
+          context.report({
+            node,
+            message: `Must never use destructuring ${node.init.callee.name} assignment`,
+          });
+        }
+
         if (SFCComponent && destructuringSFC && configuration === 'never') {
           report(context, messages.noDestructAssignment, 'noDestructAssignment', {
             node,
diff --git a/tests/lib/rules/destructuring-assignment.js b/tests/lib/rules/destructuring-assignment.js
index 738a9800ec..6c89907f29 100644
--- a/tests/lib/rules/destructuring-assignment.js
+++ b/tests/lib/rules/destructuring-assignment.js
@@ -358,6 +358,70 @@ ruleTester.run('destructuring-assignment', rule, {
       `,
       options: ['always', { destructureInSignature: 'always' }],
     },
+    {
+      code: `
+        import { useContext } from 'react';
+
+        const MyComponent = (props) => {
+          const {foo} = useContext(aContext);
+          return <div>{foo}</div>
+        };
+      `,
+      options: ['always'],
+      settings: { react: { version: '16.9.0' } },
+    },
+    {
+      code: `
+        import { useContext } from 'react';
+
+        const MyComponent = (props) => {
+          const foo = useContext(aContext);
+          return <div>{foo.test}</div>
+        };
+      `,
+      options: ['never'],
+      settings: { react: { version: '16.9.0' } },
+    },
+    {
+      code: `
+        const MyComponent = (props) => {
+          const foo = useContext(aContext);
+          return <div>{foo.test}</div>
+        };
+      `,
+      options: ['always'],
+      settings: { react: { version: '16.8.999' } },
+    },
+    {
+      code: `
+        const MyComponent = (props) => {
+          const {foo} = useContext(aContext);
+          return <div>{foo}</div>
+        };
+      `,
+      options: ['never'],
+      settings: { react: { version: '16.8.999' } },
+    },
+    {
+      code: `
+        const MyComponent = (props) => {
+          const {foo} = useContext(aContext);
+          return <div>{foo}</div>
+        };
+      `,
+      options: ['always'],
+      settings: { react: { version: '16.8.999' } },
+    },
+    {
+      code: `
+        const MyComponent = (props) => {
+          const foo = useContext(aContext);
+          return <div>{foo.test}</div>
+        };
+      `,
+      options: ['never'],
+      settings: { react: { version: '16.8.999' } },
+    },
   ]),
 
   invalid: parsers.all([].concat(
@@ -785,6 +849,36 @@ ruleTester.run('destructuring-assignment', rule, {
         `,
         features: ['ts', 'no-babel'],
       },
-    ] : []
+    ] : [],
+    {
+      code: `
+        import { useContext } from 'react';
+
+        const MyComponent = (props) => {
+          const foo = useContext(aContext);
+          return <div>{foo.test}</div>
+        };
+      `,
+      options: ['always'],
+      settings: { react: { version: '16.9.0' } },
+      errors: [
+        { message: 'Must use destructuring foo assignment' },
+      ],
+    },
+    {
+      code: `
+        import { useContext } from 'react';
+
+        const MyComponent = (props) => {
+          const {foo} = useContext(aContext);
+          return <div>{foo}</div>
+        };
+      `,
+      options: ['never'],
+      settings: { react: { version: '16.9.0' } },
+      errors: [
+        { message: 'Must never use destructuring useContext assignment' },
+      ],
+    }
   )),
 });